Guest post by Dr. Don J. Easterbrook
1934 has long been considered the warmest year of the past century. A decade ago, the closest challenger appeared to be 1998, a super-el nino year, but it trailed 1934 by 0.54°C (0.97°F). Since then, NASA GISS has “adjusted” the U.S. data for 1934 downward and 1998 upward (see December 25, 2010 post by Ira Glickstein) in an attempt to make 1998 warmer than 1934 and seemingly erased the original rather large lead of 1934 over 1998. The last phases of the strong 2009-2010 el nino in early 2010 made this year another possible contender for the warmest year of the century. However, December 2010 has been one of the coldest Decembers in a century in many parts of the world, so 2010 probably won’t be warmer than 1998. But does it really matter? Regardless of which year wins the temperature adjustment battle, how significant will that be? To answer that question, we need to look at a much longer time frame‒centuries and millennia.
One of the best ways to look at long-term temperatures is with isotope data from the GISP2 Greenland ice core, from which temperatures for thousands of years can be determined. The ice core isotope data were obtained by Minze Stuiver and Peter Grootes from nuclear accelerator measurements of thousands of oxygen isotope ratios (16O/18O), which are a measure of paleo-temperatures at the time snow fell that was later converted to glacial ice. The age of such temperatures can be accurately measured from annual layers of accumulation of rock debris marking each summer’s melting of ice and concentration of rock debris on the glacier.
The past century
Two episodes of global warming and two episodes of global cooling occurred during the past century:
1880 to 1915 cool period. Atmospheric temperature measurements, glacier fluctuations, and oxygen isotope data from Greenland ice cores all record a cool period from about 1880 to about 1915. Many cold temperature records in North America were set during this period. Glaciers advanced, some nearly to terminal positions reached during the Little Ice Age about 400 years ago. During this period, global temperatures were about 0.9 ° C (1.6 ° F) cooler than at present. From 1880 to 1890, temperatures dropped 0.35 ° C (0.6° F) in only 10 years. The 1880 –1915 cool period shows up well in the oxygen isotope curve of the Greenland Ice Sheet.
1915 to 1945 warm period. Global temperatures rose steadily in the 1920s, 1930s, and early 1940s. By the mid-1940s, global temperatures were about 0.5 °C (0.9° F) warmer than they had been at the turn of the century. More high temperature records for the century were recorded in the 1930s than in any other decade of the 20th century. Glaciers during this warm period retreated, temperatures in the 1930s in Greenland were warmer than at present, and rates of warming were higher (warming 4°C (7° F) in two decades). All of this occurred before CO2 emissions began to soar after 1945, so at least half of the warming of the past century cannot have been caused by manmade CO2.
1945 to 1977 cool period. Global temperatures began to cool in the mid–1940’s at the point when CO2 emissions began to soar. Global temperatures in the Northern Hemisphere dropped about 0.5° C (0.9° F) from the mid-1940s until 1977 and temperatures globally cooled about 0.2° C (0.4° F). Many of the world’s glaciers advanced during this time and recovered a good deal of the ice lost during the 1915–1945 warm period. Many examples of glacial recession cited in the news media show contrasting terminal positions beginning with the maximum extent at the end of the 1880-1915 year cool period and ending with the minimum extent of the recent 20 year warm period (1977-1998). A much better gauge of the effect of climate on glaciers would be to compare glacier terminal positions between the ends of successive cool periods or the ends of successive warm periods.
1977 to 1998 global warming The global cooling that prevailed from ~1945 to 1977 ended abruptly in 1977 when the Pacific Ocean shifted from its cool mode to its warm mode in a single year and global temperatures began to rise, initiating two decades of global warming. This sudden reversal of climate in 1977 has been called the “Great Pacific Climate Shift” because it happened so abruptly. During this warm period, alpine glaciers retreated, Arctic sea ice diminished, melting of the Greenland Ice Sheet occur.
The abruptness of the shift in Pacific sea surface temperatures and corresponding change from global cooling to global warming in 1977 is highly significant and strongly suggests a cause-and-effect relationship. The rise of atmospheric CO2, which accelerated after 1945 shows no sudden change that could account for the “Great Pacific Climate Shift”.
1999 to 2010 global cooling. No global warming has occurred above the 1998 level and temperatures have declined slightly.
The past 500 years
Temperature oscillations recorded in Greenland ice cores over the past 500 years (Fig. 2) are truly remarkable. At least 40 periods of warming and cooling have occurred since 1480 AD, all well before CO2 emissions could have been a factor.
The past 5,000 years
Figure 3 shows oxygen isotope ratios from the GISP2 Greenland ice core for the past 5,000 years. Note that temperatures were significantly warmer than present from 1500 to 5000 years ago.
The past 10,000 years
Most of the past 10,000 have been warmer than the present. Figure 4 shows temperatures from the GISP2 Greenland ice core. With the exception of a brief cool period about 8,200 years ago, the entire period from 1,500 to 10,500 years ago was significantly warmer than present.
Another graph of temperatures from the Greenland ice core for the past 10,000 years is shown in Figure 5. It shows essentially the same temperatures as Cuffy and Clow (1997) but with somewhat greater detail. What both of these temperature curves show is that virtually all of the past 10,000 years has been warmer than the present.
So where do the 1934/1998/2010 warm years rank in the long-term list of warm years? Of the past 10,500 years, 9,100 were warmer than 1934/1998/2010. Thus, regardless of which year ( 1934, 1998, or 2010) turns out to be the warmest of the past century, that year will rank number 9,099 in the long-term list.
The climate has been warming slowly since the Little Ice Age (Fig. 5), but it has quite a ways to go yet before reaching the temperature levels that persisted for nearly all of the past 10,500 years.
It’s really much to do about nothing.
Smokey, you and others quote Richard Alley approvingly, implying that he agrees with Don Easterbrook. He does not.
This is what Richard Alley said earlier this week in a correction to a story in the NY Times:
“I continue to believe that the assessments of the IPCC, and the National Academy of Sciences, provide our best guide to the effects of carbon dioxide on climate. My statements were intended to communicate the assessed science.
The interested reader might start with Figure 1 in Box 10.2 in chapter 10 of the I.P.C.C. Working Group 1 Fourth Assessment Report. The best estimate of climate sensitivity is near 3 degrees Centigrade of warming, or 5 to 6 degrees Fahrenheit, for equilibrium response to doubled CO2, but with an uncertainty range that extends further to higher values than to lower ones. As shown there, if one wants to be highly confident that the stated uncertainty range includes all possibilities, sensitivity as high as 8 or 9 degrees Centigrade, or 14 to 16 degrees Fahrenheit, is at least slightly possible based on some analyses. Proper quantification is given there and in the references cited by the I.P.C.C. report.”
As you ask: “So, who to believe?” You’ve got to choose between Alley and Easterbook.
You can see a video as Alley describes how the GISP2 ice cores from Greenland were drilled, collected, analyzed, and interpreted at: this link
Easterbrook wants to use Alley’s data, while saying that Alley completely misinterprets it.
Again, Smokey, “Who to believe?” Listen to Alley and tell me what you think.
Oregon Perspective: Let’s do some basic math for Richard Alley (since he has a few problems in this area).
If 9.0C per doubling was correct, what should the temperature have increased so far?
Temp C Increase = +4.3C = 9/ln(2)*ln(390/280)
So Alley is only off by a factor of 6 so far.
He gave the Bjerknes lecture last year at the fall AGU meeting on the CO2 sensitivity based on the paleoclimate data. One can only see less than 3.0C per doubling (more like 1.5C per doubling) in that data so why would he now try to quote a figure which is more than three times higher. It is disingenuous at best.
When I plotted the GISP2 data, my numbers all came out 0.5 degrees Centigrade lower than the ones shown in Figure 5. Is there an adjustment I missed?
Bill, why do you use a sensitivity of 9 degrees F for a doubling of CO2 that is 3 times the sensitivity of 3 degrees C that you yourself say Alley endorses.
Apparently, just to smear him.
Again, “Why?”
Sorry, “9 degrees C”
Oregon Perspective,
Sorry I didn’t make my response clearer. I was referring to both the article, and to the chart from the Journal of Quaternary Science Reviews, which is based on Alley’s data. I agree that Alley flip-flops, which wrecks his credibility.
But I was responding to Peru, who flatly stated that “in a century we are back, in Greenland, to the warmth of the Minoan Warming and the Holocene Maximum.” The chart based on Alley’s data shows that isn’t true. And in the article Dr Easterbrook also shows that it isn’t true.
Oregon,
The way I read his post, I don’t think Bill Illis is using a 9° sensitivity. Bill said 1.5°C. He knows more than I do about this particular subject, so I’ll defer to him. But if I were to make a SWAG, I would say <1°C.
Smokey, do you review your sources?
That chart is not “from the Journal of Quaternary Science Reviews”, as you claim. The chart was supposedly put together from Alley’s data by David Lappi, a petroleum geologist from Alaska without any experience in ice cores or climate science. The chart has never been peer-reviewed for publication, so don’t imply it has.
Even if we accept it without review, the chart does not include the last 105 years of temperature change in Greenland, which is likely greater than the global temperature change of 0.79 degrees C over that period.
As noted elsewhere, Easterbrook’s data has the same flaws. It is missing the last 100 years of temperature change and has never been peer-reviewed.
Again, “Why?”
From Peru says:
December 30, 2010 at 2:27 pm
Bob from the UK says:
December 30, 2010 at 1:39 am
“I see on the graph in figure 5 that the bottom axis ends in 1905 (95) so what exactly is your point?”
My point is that Dr. Don J. Easterbrook used the data as if the end of the timeseries is the present (it is no clue in text about it, that text argument as if the graph end in the present. The only clue is in the small labels in the x-scales that easily are lost. This is the “small letters trick”, a common commercial trick used to deceive the consumer).
It’s actually worse than that because the legend of the graph has had ‘2000AD’ added to indicate ‘present’ which is incorrect, in this context ‘years before present’ means years before 1950′! Consequently the last data shown is for 1855AD.
A larger problem for Bill, Smokey, and Easterbrook is that you all are just cherry picking charts and data that support your case. That’s not science, that’s propaganda.
As I noted above, 15 years of peer-review of Alley’s GISP2 data shows that GISP2 temperatures are not very representative of global temperature, as noted in tens of publications over the last 15 years, including a 2002 review by Alley.
You and Easterboork also choose to ignore the other publications that put the GISP2 data in a global context or other data and confounding climate processes. See Barker in Nature 2009, and or Sigman in Nature, 2010 as examples. Pdfs of these are available online.
Again, why do you cherry pick data and ignore contrary evidence?
Are your interests science or propaganda?
Oregon Perspective:
You are the one who quoted Richard Alley’s assertion that the CO2 sensitivity could be as high as 9.0C per doubling. In fact, you are just quoting the quote he gave in the New York Times no less (“the New York Times” no less to say it again). He even started with a 20 degree number before correcting it twice.
I’m sorry, but your hero has a problem with basic math (either that or he has a serious problem with exaggeration including in his peer-reviewed papers).
Oregon Perspective,
I read the provenance of the chart, which is right in the chart itself; center near the bottom. It also states that the data is from Alley.
And I didn’t “imply” that the chart is peer reviewed – not that climate peer review is anything but “pal review”: Michael Mann’s recent paper based on the Tiljander proxy was hand-waved through peer review, even though it is documented that Mann knew before he submitted his paper that the Tiljander proxy changed the sign; it was corrupted from road grading. But Mann used it anyway, knowing his referee pals could be counted on to chalk up another bogus climate paper. Climate pal review is important to you. To me, not so much.
Dr Easterbrook’s chart also confirms that the Holocene had numeous temperature rises just like the one we’re going through. Occam’s Razor says that the current rise is simply natural variability.
And the question of the last century has been addressed to my satisfaction, and that of most other commentators. So why is it so important to you that the current *mild* 0.7° rise must equal the Minoan? That proves nothing, even if it were true. Your contention isn’t supported by the data I’ve seen and posted, but you seem rather desperate to alarm the populace.
Relax, CO2 isn’t gonna getcha. If you have to worry, then worry about asteroids. Unlike CAGW, that is a real threat.
I realize that James Hansen is both incompetent and criminally liable for faking data and fueling the false fires of AGW, but why is NASA in general becoming more and more involved in climate and temperature discussions? Is it because they have nothing to do these days and they need a purpose of crisis to justify their existence and umm budget? Every few months or so, they come out with some assinine statement about pretty much nothing just to make people remember they are there. So has the head of NASA decided to give Hansen more visibility or something to garner a greater role in “fighting AGW”? Just trying to analyze what they have been up to lately.
Smokey says:
“Currently we are 2 – 3° below the Minoan Optimum. The temperature has risen by a mild 0.7°C over the past century; something that has occurred repeatedly and often throughout the Holocene”
Mr Smokey, that “mild 0.7ºC” is the GLOBAL average.
The GISP2 data if from an ice core in GREENLAND, so you must compare the ancient temperatures in Greenland to modern temperatures THERE . In Greenland the warming between the 1900-1910 decade and the 2000-2010 decade is between 2ºC and 4ºC. And the Holocene Maximum and the Minoan Warm Period were 3ºC warmer than in 1905. So we are back to the temperatures seen in those ancient warm periods.
If you want the graph, it is here:
http://data.giss.nasa.gov/cgi-bin/gistemp/do_nmap.py?year_last=2010&month_last=11&sat=4&sst=1&type=anoms&mean_gen=1212&year1=2000&year2=2010&base1=1900&base2=1910&radius=250&pol=reg
Based on the stations in Greenland:
http://data.giss.nasa.gov/cgi-bin/gistemp/findstation.py?datatype=gistemp&data_set=1&name=&world_map.x=291&world_map.y=42
“But I was responding to Peru, who flatly stated that “in a century we are back, in Greenland, to the warmth of the Minoan Warming and the Holocene Maximum.” The chart based on Alley’s data shows that isn’t true. And in the article Dr Easterbrook also shows that it isn’t true”
What is not true is your the conclusions you draw from a mutilated graph that ends in 1905, ignoring 105 years of warming, that clearly show a warming between 2ºC and 4ºC. You are clearly wrong, and you refuse to recognize that. You claim I am “desperate” but clearly that is a description for yourself as you refuse to accept the reality of this planet, specifically the reality of the last 105 years in Greenland.
Omitting the last 105 years of warming is clearly a deception. I do not know is it is voluntary (in that case this a blatant lie) or just self-deceptive willful ignorance.
From Peru can’t think straight. Cognitive dissonance in action.
He claims there was a 2 – 4° temperature rise over the past century, when even the IPCC says the rise was only 0.7°. Contradicting himself, he admits that the 0.7° [natural] rise is a “GLOBAL average.”
Well, DUH!
CAGW alarmists belong to a doomsday cult, the same as Mrs Keech’s flying saucer cult, or the Jehovah’s Witnesses doomsday cult. There is no reasoning with such cognitive dissonance-afflicted alarmists.
CO2 is a total non-problem. But True Believers’ minds are made up and closed tight.
The scientific method would clear things up for them, but nothing can penetrate their belief systems.
Henry@From Peru
Just to be clear on this:
If someone claims that global warming is caused by an increase in carbon dioxide it is actually up to that person making the claim to provide me with the evidence. In this respect I would need to see clear results in the relevant concentration range and it must show how much cooling and how much warming is caused by the CO2. This would have to include the radiative cooling caused by CO2 and the cooling by CO2 caused by taking part in the process of photo synthesis. In fact, I am puzzled why no one, even if it were Anthony or Willis or someone, does not sue people like Al Gore and them in a court of law for making false claims.
So if you make the claim (to me) that carbon dioxide is the cause of global warming, it is up to you to provide me with that evidence. For that, I would expect you to show me exact test results and the method and instruments used to get those results.
People I corresponded with like Weart and Alley, all claim, like you, that those results
do actually exist. Well, I could not find them.
IPPC and them used a system whereby the increase of CO2 and other GHG’s were measured from 1750 to 2005 and then a value of forcing was attributed to each of them according to the warming observed. This would make sense if we knew for sure that GHG’s are the cause of modern warming.
But, surely, that is looking at a problem from the wrong end? That is assuming you know what is causing warming and then working your way back. It is the worst mistake any scientist can make.
To be completely truthful, I did make a similar mistake myself in the past. It happens when you get carried away too much with what you think is right or what you think ought to be.
So, I know what went wrong here. There is a complete lack of actual test results and everybody thought that it must be the CO2, “because what else can it be? There must something that we are doing wrong….” Well actually my finding is that carbon dioxide is good for life and more of it is better….
By saying that CO2 is not the cause of modern warming, I am not saying that warming is not happening. Modern warming could have natural causes or it could have some element being manmade, that is what we have to figure out. If you have read my blog,
http://www.letterdash.com/HenryP/more-carbon-dioxide-is-ok-ok
and you understand what I am saying there, then it seems that modern warming is definitely not caused by GHG’s, as in that case the minimum temps should show a higher increase. I could not find this in the two examples of weather stations that I looked at (that had some relevant data going back 50-100 years)
Do you have data from stations in Peru? Was Peru not having a very bad winter this year? How many died? Aren’t you worried about that happening again?
Henry, claims: “If someone claims that global warming is caused by an increase in carbon dioxide it is actually up to that person making the claim to provide me with the evidence.” “Well, I could not find them.”
Henry you’ll find it here: https://www.ipcc-wg1.unibe.ch/publications/wg1-ar4/wg1-ar4.html
For this 2007 Fourth Assessment Report of the Intergovernmental Panel on Climate Change reviewed 14 global climate models from all major climate centers, and ran many simulations on those climate models using both natural and anthropogenic forcings.
Henry, you’ll find the models reviewed in Chapter 8 (pp. 589-662) and the simulation results with both natural and anthropogen forcings in Chapter 9 (pp. 663f-746).
You’ll find the final conclusions on p. 727: “No known mode of internal variability [that is, natural forcing] leads to such widespread, near universal warming as has been observed in the past few decades.” “Greenhouse gas forcing is the dominant cause of warming during the past several decades.” And also in the executive (https://www.ipcc-wg1.unibe.ch/publications/wg1-ar4/ar4-wg1-spm.pdf) and technical (https://www.ipcc-wg1.unibe.ch/publications/wg1-ar4/ar4-wg1-ts.pdf) summaries.
Ah, but I suspect you’ll say the 89 scientists that authored Chapter 8 and the 54 that authored Chapter 9, or the 10s of scientist that compiled the summaries, don’t know what you know.
As Smokey said, the question is, “Who to believe.”
Oregon Perspective, you said:
“That chart is not “from the Journal of Quaternary Science Reviews”, as you claim. The chart was supposedly put together from Alley’s data by David Lappi, a petroleum geologist from Alaska without any experience in ice cores or climate science. ”
If you are talking about the data that went into Figure 5 of this post, I got essentially the same data (although with a 0.5 Centigrade bias) from NOAA:
ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/gisp2/isotopes/gisp2_temp_accum_alley2000.txt
In order to bridge the gap between 1905 (the end date for the GISP2 data) and the present day, one can use the instrumental record for the last 140 years by the Danish Meteorological Institute (DMI). Take a look:
http://diggingintheclay.wordpress.com/2010/12/30/dorothy-behind-the-curtain-part-2/
The first sentence of this post by Easterbrook starts with a misleading comparison about the 1930s. It then moves on to some slights of the hand, in which 1905 is described as “the present.” I just don’t see how anyone with a skeptical bone in their bodies would trust the following calculations for which no methods are given. One might also ask whether proxies other than O18, give the same results. O18 may be a useful proxy for temperature, but I would like to see comparisons between O18 and other proxies and even, recent instrumental data, if possible. Would you accept the O18 data so readily and completely if the analysis supported ACW? I like to go back to the original data, where possible. However, Easterbook does not give enough methods to make this possible.
BillD,
While you were typing, gallopingcamel gave the answer to your question. And you are presuming that Dr Easterbrook is being sly just because he didn’t write his article exactly as you want. That lame argument is simply alarmist projection. Why not write him and ask for his comment? You might learn something.
OTOH, if you want to see outright, provable dishonesty and scientific fraud, you need look no further than MBH98/99, upon which the AR-4 conclusions are based [along with plenty of amateur input from the WWF and other NGOs]. Read A.W. Montford’s The Hockey Stick Illusion, available along the right sidebar. Then report back on your view of Mann’s outrageous scientific misconduct.
Oregon Perspective says:
“No known mode of internal variability [that is, natural forcing] leads to such widespread, near universal warming as has been observed in the past few decades.”
That is a classic Argumentum ad Ignorantium: “We don’t know what causes climate variability. Therefore…
“Greenhouse gas forcing is the dominant cause of warming during the past several decades.”
Translation: “We do not understand how the climate really works. But we’re getting paid big bucks to conclude that the cause of current climate activity, which cannot be discerned from entirely natural past variability patterns, must be ‘greenhouse’ gases this time around.” That’s about it, eh?
Once again: zero scientific method employed, prominenet appeals to [well paid, biased] authority, rampant conjecture, and claimed consensus. The IPCC puts out anti-science hogwash and calls it science. But science without the scientific method is pseudo-science.
Doomsday cultists are nothing if not gullible.
Thank you for a most informative interpretation of climate cycles I believe I may have ever seen that the average person can easily understand. Armed with this info, my kids will be better prepared to defend themselves against the brainwashing attempts of many of their peers and teachers!
Hi Oregon perspective
I am so glad you know and understand what is going on here.
I am sure you think 89 scientists must be able to somehow come up to you with the answers that you and I have been looking for.
Well, all I need you to tell me eaxactly is how much (radiative) warming and how much (radiative) cooling is caused by the increase of 0,01% CO2 that occurred in the past 50 years.The snag is; I don’t need assumptions, models, and mathematical calculations. I don’t trust those. I want to see actual test results obtained during a real experiment.
The unit is a giveaway:
it must be in W/m2/0.01% CO2/unit of time, for the (radiative) warming and it must be in W/m2/0.01 % CO2/unit of time for the (radiative) cooling
We would also need to know how much cooling is caused by the CO2 by taking part in the process of photo synthesis. Because at the end of the day: the question is what is the net effect of the cooling and warming caused by CO2?
As I said before, the IPCC evaluated “forcing” of each GHG by comparing the increase of GHG’s with the modern warming taking 1750 as the zero point. (see chapter 2 of your quote to me). It is just like they “knew” exactly what was causing warming and started working from there, namely an increase in GHG’s.
they do not have the actual test results that I am looking for.
So it is back to zero (Start). I am saying that GHG’s did not cause modern warming, because of what we see at weather stations: No increase in average minimum temps that matches modern warming. If GHG’s caused modern warming it would have been minimum temps. that should show a steeper increase (heat being trapped during the colder part of the day – night time). Yet, those are flat.
http://www.letterdash.com/HenryP/more-carbon-dioxide-is-ok-ok
[Snip. Per the Policy page, comments that contain the pejorative “denialists”, “deniers,” etc. will be snipped. ~dbs, Mod.]
Smokey says:
December 30, 2010 at 9:34 pm
“From Peru can’t think straight. Cognitive dissonance in action.”
That sentence describes you. Because you say:
“He claims there was a 2 – 4° temperature rise over the past century, when even the IPCC says the rise was only 0.7°. Contradicting himself, he admits that the 0.7° [natural] rise is a “GLOBAL average.”
Well, DUH!”
We are talking about GREENLAND, since the GISP2 data is from an ice core in GREENLAND. If you compare the ice core temperature proxies from Greenland and then you compare it with the global average instrumental temperature record, you are comparing apples with oranges.
I give you a map that shows a warming between 2ºC and 4ºC in GREENLAND, and a list of the stations in GREENLAND that measured that warming.
It is not clear?
Then you go to say:
“CAGW alarmists belong to a doomsday cult, the same as Mrs Keech’s flying saucer cult, or the Jehovah’s Witnesses doomsday cult. There is no reasoning with such cognitive dissonance-afflicted alarmists.
CO2 is a total non-problem. But True Believers’ minds are made up and closed tight.
The scientific method would clear things up for them, but nothing can penetrate their belief systems.”
You talk abou the scientific method, but you use abundantly half-truths (like mutilated graphs) and flawed comparisons that have nothing to do with the scientific method.
I will wait until your response. If you still doesn’t undestand the difference between GREENLAND and the GLOBE, you really will show that “nothing can penetrate your belief system.”